The CDC 1604 is a 48-bit computer designed and manufactured by
Seymour Cray
Seymour Roger Cray (September 28, 1925 – October 5, 1996) – was an American
Control Data Corporation
Control Data Corporation (CDC) was a mainframe and supercomputer company that in the 1960s was one of the nine major U.S. computer companies, which group included IBM, the Burroughs Corporation, and the Digital Equipment Corporation (DEC), the N ...
(CDC). The 1604 is known as one of the first commercially successful transistorized computers. (The
IBM 7090
The IBM 7090 is a second-generation Transistor computer, transistorized version of the earlier IBM 709 vacuum tube mainframe computer that was designed for "large-scale scientific and technological applications". The 7090 is the fourth member o ...
was delivered earlier, in November 1959.) Legend has it that the 1604 designation was chosen by adding CDC's first street address (501 Park Avenue) to Cray's former project, the ERA- UNIVAC 1103.
A cut-down 24-bit version, designated the
CDC 924
The CDC 1604 is a 48-bit computing, 48-bit computer designed and manufactured by Seymour Cray and his team at the Control Data Corporation (CDC). The 1604 is known as one of the first commercially successful transistor computer, transistorized co ...
, was shortly thereafter produced, and delivered to NASA.
The first 1604 was delivered to the U.S. Navy Post Graduate School in January 1960 for JOVIAL applications supporting major Fleet Operations Control Centers primarily for weather prediction in
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
,
London
London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...
, and
Norfolk, Virginia
Norfolk ( ) is an independent city (United States), independent city in the U.S. state of Virginia. It had a population of 238,005 at the 2020 United States census, 2020 census, making it the List of cities in Virginia, third-most populous city ...
. By 1964, over 50 systems were built. The
CDC 3600
The CDC 3000 series ("thirty-six hundred" or "thirty-one hundred") are a family of mainframe computer, mainframe computers from Control Data Corporation (CDC). The first member, the CDC 3600, was a 48-bit computing, 48-bit system introduced in 196 ...
, which added five op codes, succeeded the 1604, and "was largely compatible" with it.
One of the 1604s was shipped to the Pentagon to DASA (Defense Atomic Support Agency) and used during the Cuban missile crises to predict possible strikes by the Soviet Union against the United States.
A 12-bit
minicomputer
A minicomputer, or colloquially mini, is a type of general-purpose computer mostly developed from the mid-1960s, built significantly smaller and sold at a much lower price than mainframe computers . By 21st century-standards however, a mini is ...
, called the CDC 160, was often used as an I/O processor in 1604 systems. A stand-alone version of the 160 called the CDC 160-A was arguably the first minicomputer.
words
A word is a basic element of language that carries meaning, can be used on its own, and is uninterruptible. Despite the fact that language speakers often have an intuitive grasp of what a word is, there is no consensus among linguists on its ...
of magnetic core memory with a cycle time of 6.4 microseconds. It is organized as two banks of 16K words each, with odd addresses in one bank and even addresses in the other. The two banks are phased 3.2 microseconds apart, so average effective memory access time was 4.8 microseconds. The computer executes about 100,000 operations per second.
Each 48-bit word contains two 24-bit instructions. The instruction format is 6-3-15: six bits for the operation code, three bits for a "designator" (index register for memory access instructions, condition for jump (branch) instructions) and fifteen bits for a memory address (or shift count, for shift instructions).
The CPU contains a 48-bit accumulator (A), a 48-bit Auxiliary Arithmetic register (Q), a 15-bit program counter (P), and six 15-bit index registers (1-6). The Q register was usually used in conjunction with A for forming a double-length register AQ or QA, participating with A in multiplication, division and logical product (masking) operations, and temporary storage of A's contents while using A for another operation.
Internal integer representation uses
ones' complement
The ones' complement of a binary number is the value obtained by inverting (flipping) all the bits in the Binary number, binary representation of the number. The name "ones' complement" refers to the fact that such an inverted value, if added t ...
arithmetic. Internal floating point format is 1-11-36: one bit of sign, eleven bits of offset (biased) binary exponent, and thirty-six bits of binary significand.
The most-significant three bits of the accumulator are converted from digital to analog and connected to a tube audio amplifier contained in the console. This facility could be used to program audio alerts for the computer operator, or to generate music. Those familiar with the inner workings of the software could often hear what parts of a task were being performed by the CDC 1604; as a debugging aid, for example, a never-ending repetitive musical phrase indicated the program was stuck in a loop.
Uses and applications
In 1960, one of the first text-mining applications, ''Masquerade'', was written for the
Marathon Oil
Marathon Oil Corporation was an American company engaged in hydrocarbon exploration. In November 2024, it was acquired by ConocoPhillips and absorbed into the company.
Marathon was founded in Lima, Ohio, as the Ohio Oil Company. In 1899, the ...
Company in
Findlay, Ohio
Findlay ( ) is a city in Hancock County, Ohio, United States, and its county seat. The second-largest city in Northwest Ohio, Findlay lies about 40 miles (64 km) south of Toledo, Ohio, Toledo. Its population was 40,313 at the 2020 United Sta ...
. Masquerade was a text-mining program that used syntactic structures underlying text data to mask out words and phrases for searching purposes.
During 1969, Fleet Operations Control Center, Pacific ( FOCCPAC at Kunia) on
Oahu
Oahu (, , sometimes written Oahu) is the third-largest and most populated island of the Hawaiian Islands and of the U.S. state of Hawaii. The state capital, Honolulu, is on Oahu's southeast coast. The island of Oahu and the uninhabited Northwe ...
in
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
launched an ''Automated Control Environment'' (ACE) using a cluster of five CDC 160As to supervise a multi-tasking network of four CDC 1604s.
The Minuteman I was the first U.S. solid-rocket ICBM system to be fielded. There were two entirely separate ground station designs which were developed independently. The smaller, more elegant, single silo design incorporated two redundant CDC 1604 computer systems, each equipped with dual cabinets containing four 200 bpi
magnetic tape
Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnetic ...
drives. The computers were used to pre-compute guidance and aiming control information. Results based on current weather and targeting information were downloaded into the missile prior to launch. Model displays of both of these ICBM ground station designs, including block models of the CDC 1604 computers, may be viewed at the Octave Chanute Aerospace Museum in Rantoul, Illinois.
The third version of the
PLATO
Plato ( ; Greek language, Greek: , ; born BC, died 348/347 BC) was an ancient Greek philosopher of the Classical Greece, Classical period who is considered a foundational thinker in Western philosophy and an innovator of the writte ...
computer-based educational system was implemented on a CDC 1604-C.
JOVIAL was used as the main programming language of the CDC 1604, while
octal
Octal (base 8) is a numeral system with eight as the base.
In the decimal system, each place is a power of ten. For example:
: \mathbf_ = \mathbf \times 10^1 + \mathbf \times 10^0
In the octal system, each place is a power of eight. For ex ...
was used to program shared services supported by the CDC 160A. NAVCOSSACT based at the
Washington Navy Yard
The Washington Navy Yard (WNY) is a ceremonial and administrative center for the United States Navy, located in the federal national capital city of Washington, D.C. (federal District of Columbia). It is the oldest shore establishment / base of ...
provided systems and training support.
The CDC 1604 was used to compose Sailboat and other artworks by Sam Schmitt and Stockton Gaines.
Similar machines
The 1604 design was used by the Soviet nuclear weapons laboratory. Their BESM-6 computer, which entered production in 1968, was designed to be somewhat software compatible with the CDC 1604, but it ran 10 times faster and had additional registers.
The 924
The CDC 924 is a 24-bit computer that supported the use of "any input-output devices capable of communicating with the 160 and/or 1604 computer," and its six independent channels permitted three simultaneous input operations even as three channels concurrently performed output.
Like many CDC processors, it used ones' complement arithmetic.
Some advanced features of the 924, which included 64 instructions, were:
* Six index registers. The value "7" was reserved to indicate indirect-addressing.
* an execute instruction (in what the hardware reference manual called "a subroutine of a single instruction").
* powerful Storage Search instructions.
See also
*
Grace Hopper
Grace Brewster Hopper (; December 9, 1906 – January 1, 1992) was an American computer scientist, mathematician, and United States Navy rear admiral. She was a pioneer of computer programming. Hopper was the first to devise the theory of mach ...
Charles Babbage Institute
The IT History Society (ITHS) is an organization that supports the history and scholarship of information technology by encouraging, fostering, and facilitating archival and historical research. Formerly known as the Charles Babbage Foundation, ...
, University of Minnesota. Engineers include Robert Moe, Wayne Specker, Dennis Grinna, Tom Rowan, Maurice Hutson, Curt Alexander, Don Pagelkopf, Maris Bergmanis, Dolan Toth, Chuck Hawley, Larry Krueger, Mike Pavlov, Dave Resnick, Howard Krohn, Bill Bhend, Kent Steiner, Raymon Kort, and Neil R. Lincoln. Discussion topics include CDC 1604,
CDC 6600
The CDC 6600 was the flagship of the 6000 series of mainframe computer systems manufactured by Control Data Corporation. Generally considered to be the first successful supercomputer, it outperformed the industry's prior recordholder, the I ...